Method of coating fabric with a modified haloprene composition



Patented 29, 1949 METHOD OF COATING FABRIC WITH A MODIFIED HALOPRENECOMPOSITION Robert N. MacDonald, New Castle, and Henry S. Rotlirock,Wilmington, Del., assignors to E I. du Pont de Nemours & Company,Wilmington, Del., a corporation of Delaware No Drawing. ApplicationMarch 14, 1947,

. Serial No. 734,848

Claims. (Cl. 117-161) This invention relates to modified haloprenecompositions and more specifically to polymers of halogen-2-butadiene1,3 (called haloprenes) modified with halogenated polyethylene.

The polymerized chloro-Z-butadiene 1,3, morecommonly known as neoprene,is the most widely does not result in premature curing of thepolymerized haloprene. If the polymerized haloprene is heated to atemperature necessary to render the halogenated polyethylene plastic, itlacks suflicient internal friction to allow the other compoundingingredients to become thoroughly disknown and used of all thehaloprenes. Neoprene is noted for its flexibility and resistance tocracking during flexing at low temperatures, a property which is highlydesirable where flexible materials are required. There are, however,certain characteristics of neoprene compositions which require furtherimprovement such as for example abrasion resistance which is of primeimportance in many industrial applications such as forexample, footwear,tires, hoses, wire coatings, coated fabrics, etc. Further improvementsare desired in the resistance of neoprene compositions to certainorganic fluids commonly used as fuel in internal combustion engines.

More recently, halogenated polyethylene has become available. It is avery stable thermoplastic material but is lackin in abrasion resistance,flexibility and resistance to cracking at low temperatures. Also, thehalogenated polyethylene is attached by organic liquids such as tolueneand benzene.

An object of this invention is to provide a method of modifyingpolymerized haloprene compositions to obtain new and useful products.Another object is to provide a method of increasing the abrasionresistance of neoprene compositions without deleteriously affecting theflexibility at low temperatures. A still further object is to provide amethod of increasing the resistance of neoprene compositions to organicsolvents such as benzene. A still further object is to provide novelmodified neoprene compositions of useful properties. Still other objectswill appear hereinafter as the description of the invention proceeds.

The objects of this invention are accomplished by mixing a polymerizedhaloprene with a halogenated polyethylene and then curing the mixture byheating above about 100 C.

It has been discovered that blends of polymerized haloprene andhalogenated polyethylene containin as low as 5 parts of halogenatedpolyethylene to 95 parts of polymerized haloprene up to equal partsyield vulcanizates having far greater abrasion resistance, hardness andinsolubility than expected on the basis of the starting materials. I

The halogenated polyethylene is a hard, brittle substance at roomtemperature and it is difficult to work on two roll mills at atemperature which Neoprene (polymerized chloroprene) persed.

In order to prepare homogeneous dispersions on a two roll rubber milland to prevent premature curing or scorching of the polymerizedhaloprene-chlorinated polyethylene compositions of this invention; it isnecessary to carry out the mixing operation .at relatively lowtemperatures (approximately 50 C.) Another method of preparin thecomposition, is to mill the haloprene polymer with the secondarycompounding ingredients such as pigments, fillers, accelerators, etc. ona cold two roll mill. The halogenated polyethylene is then mixed withthe milled haloprene polymer composition together with an oranic solventwhich is a mutual solvent for the haloprene polymer and halogenatedpolyethylene to form a substantially homogeneous composition.

Another method of mixing is to pre-mill thepolymerized haloprene withthe pigments, fillers, accelerators, etc. and then mixing the halogenated polyethylene with the milled haloprene polymer composition in akneading machine while under pressure and heated sufliciently to justsoften the halogenated polyethylene to permit adequate dispersion butinsufliciently to cause premature curing of the haloprene. A suitabletype of mixing machine for this purpose is known as a Banbury mixer.

The following is a detailed description of various methods of preparingthe compositions of this invention.

Example I An oil and gasoline resistant rubber-like compound wasprepared as follows:

Parts by weight .9.0 Chlorinated polyethylene chlorine) 4.5 Sulfur 0.072Magnesium oxide 0.9 Neozone D (phenyl, beta, naphthylamine) 0.072Stearic acid 0.144 Cumarone resin 0.6 Calcium carbonate 9.0 Carbon black11.2 Pine tar 0.6 Zinc oxide 0.9 Rosin 0.6

aseaaae The neoprene and chlorinated polyethylene were milled togetheron a two roll rubber mill at 50 C. but did not appear entirelycompatible at this stage of manufacture. It was not possible to heat thecomposition sufllciently to render the chlorinated polyethylene plasticwithout scorching the neoprene. The remaining ingredients were thenadded in the order listed and the milling continued until a.substantially homogenous composition was obtained. At this stage ofmanufacture, the composition was relatively hard and somewhat brittleand not as tacky as a control sample which differed only in that thechlorinated polyethylene was omitted and the remaining ingredients werepresent in the same ratios as listed above. The milled compositioncontaining the chlorinated polyethylene was sheeted and then vulcanizedat 142 C. for 50 minutes.

Example If Example II, Example I comm] Ratio of Chlorinated Polyethyleneto Neo rene 1:2 Film hickness.... inches.. .08l .095 Tensile Strength.p. s. L. 1,270 1,319 Volume Increase After 48 Hour Soak in Benzene percent. 11-1 144 Loss in Weight After 48 Hour Soak in Benzene and thendried.. .per cent. 8 l. 9

The following additional examples were prepared by providing a masterbatch of neoprene, pigments, fillers. and accelerators prepared bymilling the following ingredients together on a cold two roll mill:

Master Batch:

Parts by weight Neoprene 400 Zinc oxide 180 Magnesium oxide 150 Calciumcarbonate 150 Colored pigments 60 The master batch was then dissolved inxylol along with chlorinated polyethylene (68% chlorine) in severalratios as outlinedbelow:

III, I Example Comm] IV V VI VII ne o o yethylene 9%: 85/15 00. 7/33. 3150/50 Master Batch by 'WL. 200 200 200 Chlorinated P yethylene (68%Chlorine) Parts by weight 4. 6 15 42. 85 Xylol .-do 250 260 260 250 250Each formulation was mixed until thoroughly dispersed, then films werecast on a glass plate and after the solvent was removed by evaporainchand a thickness of .090".

The following test results were obtained on the various films:

Example gg- IV v V! vn Ratio of Neo rene to Chlorinate Polyothylone.95/5 /15 06. 7/33. 3 50/50 Shore A Durorneter Hardness 72 73 77 82 UModulus at 100% Elasticity. .-......p.s. i... 510 490 650 610 730Tensile Strength. do i, 340 l, 300 1, 040 8l0 770 The compositions(Examples 111 to VII) described above were also coated on a woven cottonfabric with a sateen weave running 1.12 yards per pound per 53" width ina plurality of coats by means of a doctor knife. Sufficient coats wereapplied to deposit approximately 13 ounces of nonvolatile components peryard 50" wide. The coated fabrics were cured for 2 hours at 260 F.

The following test results were obtained on the coated fabric samples:

IV V VI VII l Control 41b. Edge Wear 500 1,200 2,000 10,0!)

Wyzenbeck Abrasion No. of Oscillations Before Coating Wears Through(2401 Emery Paper) 5,000

A description of the Wyzenbeek Abrasion Test will be found in paragraphF-29, Federal Specification KK-L-136b for leather; artificial(upholstery). dated October 8, 1945.

The "Edge Wear test is conducted with the Wyzenbeek abrasion apparatusin which the abradlng surface is #10 duck and 2" x 4" sample to betested is stretched over a curved surface in such a manner that an areaof approximately by 2" is pressed against the #10 duck with a 4 lb.weight. The sample is held stationary and the #10 duck is rocked backand forth through approximately a 22 arc.

In all the above examples, only the chlorine substituted butadienepolymer known as neoprene is disclosed. However, similar halogensubstituted butadiene polymers such as polymerized bromo-2-butadiene-1,3are generally applicable for use in the compositions of this invention.The invention will be considered as including within its scope allhalogen-2-butadiene-1,3 polymers for the purposes described. Thehalogen-2- butadiene-1,3 polymers are described in U. 8. Patent1,967,863 and several applications mentioned in the patent.

In the above compositions, brominated polyethylene can be used in placeof chlorinated polyethylene with comparable results. In general, inpreparing films containing brominated polyethylene a slightly greateramount of the brominated polymer will be required than the chlorinatedpolymer to obtain compositions of comparable properties due to theatomic weight of bromine being greater than chlorine. As indicated inthe various examples, the ratio of halogen-2-butadiene 1,3 to thehalogenated polyethylene may vary between :5 and 50:50.

The degree of abrasion resistance of the compositions of this inventionwill vary with the halogen content of the halogenated polymer. The

minimum amount of halogen in the halogenated polyethylene which resultsin the most useful compositions for abrasion resistance appears to beapproximately 25% and the maximum approximately '72%. The preferredrange of halogen in the halogenated polyethylene is 40% to 70%. Ingeneral, the abrasion resistance of the compositions will increase withthe amount of halogen in the halogenated polyethylene. Therefore, it ismore advantageous to use the higher halogen containing polymers wherethe halogenated polyethylene content is low.

The outstanding property realized by blending neoprene and chlorinatedpolyethylene is abrasion resistance. This is particularly surprising andunexpected in view of the properties of neoprene and chlorinatedpolyethylene. The compositions of this invention will find utility forany application of neoprene where improved abrasion resistance isdesired. The potential end products include tires, printing rolls,printers blanket, floor covering, hose, industrial coated fabrics,gaskets, unsupported film and sheet stock and many molded articles. Thecoated fabrics of this invention are particularly useful for upholsterymaterial where heavy duty material is required such as, e. g., truckseats, theater seats, or wherever coated fabric upholstery material hasbeen used in the past. The oil and hydrocarbon resistance of thecompositions of this invention make them particularly useful for fuelpump diaphragms, fuel tanks, tubing, etc.

It is apparent that many widely different embodiments of this inventionmay be made without departing from the spirit and scope thereof, andtherefore, it is not intended to be limited except as indicated in theappended claims.

I claim: 7

1. A composition of matter which yields on curing a tough, dense, highlyabrasion-resistant film; comprising polymerized halogen-2-butadiene 1,3and halogenated polyethylene, the ratio of the ingredients being between95 parts ofhalogen-2-butadiene 1,3 to 5 parts of halogenatedpolyethylene and equal parts of the two polymers, the halogen of bothpolymers being selected from the group consisting of chlorine andbromine.

2. The composition of claim 1 in which the mixture is vulcanized.

3. The composition of claim 1 in which the halogen is chlorine.

4. The composition of claim 1 in which the halogen is bromine.

5. A fabric having an adherent coating of the vulcanized composition ofclaim 1.

6. The composition of claim 1 in which the halogen content of thehalogenated polyethylene is between 25% and 72%.

7. The composition of claim 1 in which the halogen in both polymers ischlorine, and the chlorine content of the chlorinated polyethylene liesbetween 40% and 70%.

8. A composition of matter having the following composition by weight:Chlorine-2-butadiene 1,3 plastic polymer 9.0 Chlorinated polyethylene(55% chlorine) 4.5

9. The method of preparing tough, dense, abrasion-resistant films whichcomprises milling a halogen-2-butadiene 1,3 plastic polymer with ahalogenated polyethylene at a temperature below 50 C., addingconventional stabilizers, antioxidant, accelerators and vulcanizingagents, continuing the mixing until the mass is homogeneous, rolling thesame out into a sheet and thereafter vulcanizing the same by heating toabove C., the ratio of the ingredients being between 95 parts ofhaIogen-Z-butadiene 1,3 to 5 parts of halogenated polyethylene and equalparts of the two polymers, the halogen of both polymers being selectedfrom the group consisting of chlorine and bromine.

10. The process of preparing coated fabrics which comprises milling acomposition having the following formula by weight:

Chlorine-2-butadiene 1,3 plastic polymer 400 Zinc oxide 180 Magnesiumoxide Calcium carbonate 150 Pigments 60 REFERENCES CITED The followingreferences are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,967,863 Collins et al July 24,1934 2,188,396 Lemon Jan. 30. 1940 2,261,760 Habgood NOV. 4, 19412,278,833 Crawford Apr. '1, 1942 2,416,069 Scott Feb. 18. 194':2,422,919 Myles et a1. June 34. 104!

